CA3076030A1

CA3076030A1 - Holder for a broaching tool

Info

Publication number: CA3076030A1
Application number: CA3076030A
Authority: CA
Inventors: Andreas Kanz; Matthias Luik
Original assignee: Hartmetall Werkzeugfabrik Paul Horn GmbH
Current assignee: Hartmetall Werkzeugfabrik Paul Horn GmbH
Priority date: 2017-10-12
Filing date: 2018-10-05
Publication date: 2019-04-18
Anticipated expiration: 2038-10-05
Also published as: CN111372710A; US11648613B2; CA3076030C; JP7026212B2; JP2020535029A; MX2020004406A; EP3694668A1; DE102017123786A1; RU2739744C1; EP3694668B1; US20200215628A1; EP3694668C0; WO2019072696A1

Abstract

The present invention relates to a holder for a slotting tool and to a slotting tool with a cutting tool (2) having a blade (20) and with a holder (1) for holding the cutting tool (2). The holder (1) has a clamping region (10) and a holding region (11), the holding region (11) having at its end facing away from the clamping region (10) a seat (13) for the cutting tool (2), which is designed and arranged in such a way that, when the cutting tool (2) is mounted in the seat (13), the blade (20) thereof projects beyond the circumferential surface of the holding region (11). The holding region (11) further has on its circumferential surface (15) a support (16) for the cutting tool. A coolant channel (40) having two outlet openings (43, 44), which are arranged laterally next to the support (16) and/or in side surfaces (161, 163) of the support (16) when seen in the circumferential direction, runs inside the holder (1).

Description

Holder for a broaching tool [0001] The present invention relates to a holder for a broaching tool and such a broaching tool.

[0002] Broaching is a machining method for introducing longitudinal slots in a wide variety of forms into a workpiece. In broaching, the broaching tool executes a linear advancing movement - the working stroke. Subsequently, removal of the broaching tool from the workpiece and a return stroke without machining take place. The feed motion for the re-moval of material takes place via the gradual displacement of the broaching tool until the desired profile depth and/or profile width is achieved.

[0003] Such a broaching tool is known from EP 2 212 041 Al. The broaching tool com-prises a cutting tool having a cutting edge and a holder for holding the cutting tool. The holder comprises a clamping region for clamping into a machine tool and a holding region for holding the cutting tool. The holding region comprises, an at its end facing away from the clamping region, a seat for the cutting tool, for example in the form of an end-face de-pression, which is configured and arranged such that, when the cutting tool is mounted in the seat, its cutting edge projects beyond the circumferential surface of the holding region.
The holding region is provided with a support for the cutting tool on its circumferential sur-face, which support absorbs forces acting on the cutting tool during processing and there-fore supports the cutting tool.

[0004] Cooling and lubrication of the machining process is also important when broach-ing. However, supplying cooling lubricant (simply referred to as coolant here) at the ma-chining point when broaching internal slots in bores is particularly difficult. In this case, a frequently used external coolant supply via hoses and lines does not adequately guide the coolant to the machining point. Therefore, broaching tools with an internal coolant supply are also used for broaching internal slots. However, the known solutions do not offer ade-quate and reliable cooling/lubrication.

[0005] The present invention is based on the object of providing a holder for a broaching tool and such a broaching tool, which ensure improved and reliable cooling/lubrication.

[0006] The object is achieved by a holder, described in claim 1, for a broaching tool, which is characterized in that a coolant channel extends in the interior of the holder, which coolant channel comprises two exit openings which, as seen in the circumferential direc-tion, are arranged laterally adjacent to the support and/or in lateral surfaces of the sup-port.

[0007] The object is further achieved by a broaching tool with a cutting tool having a cut-ting edge and a holder, proposed according to the invention, for holding the cutting tool.

[0008] In the holder according to the invention, the coolant therefore flows through the holder, wherein this guidance of the coolant through the coolant channel is configured such that it exits laterally adjacent to and/or at the support, i.e. in the immediate vicinity of the cutting tool. It is thus ensured, on the one hand, that the coolant does not have to cov-er a long distance to the machining point after exiting from the exiting openings, and therefore reliably impinges the cutting tool. Reliable cooling and lubrication can further-more also be ensured for long processing depths in bores. The coolant also impinges reli-ably the machining point at the start of the machining process, i.e. when the broaching tool begins the machining process at the start of a bore, for instance, and not only once a certain length has been machined in the bore. Finally, this also prevents the problem of a chip between the machining point and an exit opening preventing the coolant from imping-ing the machining point, since the coolant impinges the cutting tool from lateral directions, where the risk of a chip being formed there is generally lower,

[0009] In a preferred refinement, it is provided that the distance of the exit openings from the seat is smaller than from the clamping region. This brings about that the best possible cooling and lubrication is achieved, i.e. that the exiting coolant impinges the machining point as accurately as possible.

[0010] In a further refinement, it is provided that the coolant channel and/or the exit open-ings are configured and arranged such that exiting coolant impinges the cutting edge and/or lateral flanks adjoining the cutting edge (also referred to as the main cutting edge) and/or corners of the cutting tool which are located between the cutting edge and the flanks. It is therefore possible to specifically determine which points of the cutting tool are to be impinged by the lubricant. In contrast to known tools, it can therefore be provided that the flanks (also referred to as auxiliary cutting edges) and/or corners of the cutting tool are specifically impinged by the coolant to bring about immediate cooling there, which contributes to a longer lifetime and a reduction in wear.

[0011] In one refinement, it is furthermore provided that the coolant channel comprises a third exit opening, which is arranged on the upper side of the support. This third exit open-ing is preferably configured and arranged such that it is aligned with the cutting edge so that coolant exiting there preferably cools the cutting edge directly, while the two lateral exit openings are aligned with the lateral flanks/auxiliary cutting edges and/or the corners between the flanks and the cutting edge.

[0012] In one refinement, it is provided that the coolant channel comprises one main channel extending through the clamping region and two lateral channels branching off from the main channel in the holding region, which two lateral channels lead into the lat-eral exit openings. This represents a simple refinement of the coolant channel, which can be produced in a cost-effective manner.

[0013] In further refinements, it is provided that the main channel merges into a third lat-eral channel, which leads into a third exit opening on the upper side of the support.

[0014] The transition between the main channel and lateral channels can be configured in different ways. In one refinement, it is provided that the lateral channels extend from the main channel arranged centrally in the inside to the respective exit opening at an angle through the holding region. It can alternatively be provided that a transverse channel, which is arranged transversely, in particular perpendicularly to the longitudinal axis of the holder or the main channel and into which the main channel leads and from which the lateral channels branch, is located between the main channel and the lateral channels.
For structural considerations, it can be advantageous, for example, to provide a trans-verse channel in order to align the exit direction of the coolant stream of the lateral chan-nels with the flanks/auxiliary cutting edges. If the diameter of the main channel is not greater than the width of the support, lateral channels connected directly to the main channel would produce an outwardly directed coolant stream, which does not arrive at the flanks laterally adjacent to the main cutting edge. The transverse channel offers flexibility here when specifying the exit direction. However, the ultimate function is substantially identical for both variants.

[0015] It goes without saying that the features mentioned above and those yet to be ex-plained below are usable not only in the combination given in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0016] Exemplary embodiments of the invention are illustrated in the drawings and will be explained in more detail in the description below. In the drawings:
Fig. 1 a perspective view of the broaching tool according to the invention as an exploded illustration;
Fig. 2 a perspective view of the broaching tool according to the invention in the assem-bled state;
Fig. 3 a perspective view of the broaching tool according to the invention from the front;
Fig. 4 a perspective view of the broaching tool according to the invention with an internal view of a first refinement of the cooling channel;
Fig. 5 a lateral sectional illustration of the embodiment shown in Fig. 4 of the broaching tool according to the invention;
Fig. 6 a plan view of the embodiment shown in Fig. 4 of the broaching tool according to the invention; and Fig. 7 a perspective view of a broaching tool according to the invention with an internal view of a second refinement of the cooling channel.

[0017] Fig. 1 shows a perspective exploded illustration of an embodiment of a broaching tool according to the invention. Figs. 2 and 3 show this embodiment in the assembled state as a perspective angled view (Fig. 2) and a perspective front view (Fig.
3). The broaching tool substantially comprises a holder 1 and a cutting tool 2. The holder 1 com-prises a clamping region 10 for clamping into a machine tool, for example a spindle, a holding region 11 for holding the cutting tool 2 and a flange 12 located in between. At its end face facing way from the clamping region 10, the holding region 11 comprises a seat 13 in which the cutting tool 2 can be received and fastened therein. The seat 13 is formed by an open depression in the end face 14 and in the circumferential surface 15 of the holding region 11. This depression comprises, starting from the depression base 130, seat walls 131 which, starting from the depression base 130, extend in a mutually diverging manner towards the circumferential surface 15 of the holding region 11. The receiving space of the seat 13 for the cutting tool 2 therefore has a V-shaped cross-section in the embodiment shown.

[0018] The rear end surface 132 of the seat 13 is located in a common plane with a sup-porting surface 160 of a support 16 (also referred to as a supporting body) so that the supporting surface 160 forms a direct continuation of the rear end surface 132 of the seat 13. A continuous planar contact surface is therefore available for the cutting tool 2 fas-tened in the seat 13, which contact surface continues radially beyond the outer circumfer-ence of the holding region 11 with the supporting surface 160 of the support 16.

[0019] The support 16 is formed on the circumferential surface 15 of the holding region 11 as an integral, radially projecting supporting body. In this case, the support 16 in this em-bodiment has the form of a block which is slightly chamfered towards its upper or outer side and which, apart from the chamfers 161, possesses an approximately square cross-section with an upper side 162 and lateral surfaces 163. This support serves in particular to introduce cutting forces and generated torques into the holding region 4 via the project-ing support in the immediate vicinity of the point of application, which contributes to a re-duction in the load torques acting on the cutting tool 2.

[0020] The cutting tool 2 has a main cutting edge 20, with which, for example, an internal slot can be broached within a bore. On its rear side opposite the main cutting edge 20, the cutting tool 2 has a planar contact surface which, when the cutting tool 2 is received in the seat 13, abuts with form fit against the rear end surface 132 and the radially continuing supporting surface 160. As can be seen in Fig. 1, a threaded bore 17 for a clamping screw 3 is located at the transition region between the end surface 132 and the supporting sur-face 160, which clamping screw is in the form of a countersunk screw which reaches through a through bore 22 in the cutting tool 2 and by means of which the cutting tool 2 can be firmly clamped into the seat 13. The fastening part 21 of the cutting tool 2 is then located with lateral walls 23 in lateral contact with the lateral walls 131 and the cutting part 24 of the cutting tool 2 which is adjacent to the main cutting edge 20 abuts against the supporting surface 160 of the support 16.

[0021] As can likewise be seen in Figs. 1 to 3, the fastening part 21 of the cutting tool 2 configured in a block shape substantially has a wedge shape, which is adapted to the V-shaped receiving cross-section of the seat 13, wherein the wedge shape in the present embodiment is rounded in the lower vertex region 25. The lateral walls 23 of the fastening part 21 which extend in a diverging manner from the vertex region 25 have surface re-gions which deviate from the planar configuration or a certain spherical design for opti-mum contact with the seat walls 131. The ends of the seat walls 131 at the depression base 130 are separated from one another by a cut-out in the form of a partial bore so that a clearance between the holder 1 and the vertex region 130 of the cutting tool 2 received in the seat 13 is generated at the depression base 130.

[0022] According to the invention, it is provided that a coolant channel 40 extends in the interior of the holder 1. This coolant channel 40 is shown in a first embodiment in Figs. 4 to 6 as a perspective angled illustration (Fig. 4), as a sectional view (Fig.
5) and as a plan view (Fig. 6). Fig. 7 shows a second embodiment of the coolant channel 40 in a perspec-tive angled illustration. The coolant channel 40 comprises a main channel 41 and at least two lateral channels 42, 43. The main channel 41 extends centrally through the clamping region 10 and preferably a short distance into the holding region 11. There, the two lateral channels 42, 43 branch off from the main channel 41. The two lateral channels 42, 43 extend at an angle through the holding region and lead into exit openings 44, 45 which, according to the invention, are arranged laterally adjacent to the support 16, as seen in the circumferential direction, and/or in the lateral surfaces 163 of said support. The exit openings 44, 45 are therefore preferably arranged completely adjacent to the support 16 (in the circumferential surface 15 of the holding region 11) or completely in the lateral sur-faces 163. However, it can also be provided that the exit openings 44, 45 are each ar-ranged partially adjacent to the support 16, i.e. in the circumferential surface 15 of the holding region 11, and partially in (or on) the adjacent lateral surface 163 of the support 16.

[0023] Coolant introduced into the main channel 41 at the entry opening 49 therefore flows through the main channel 41 and the lateral channels 42, 43 until it exits at the exit openings 44, 45. Since these exit openings 44, 45 are arranged in the immediate vicinity of the cutting tool 2, the coolant impinges reliably the cutting part 24 thereof in order to bring about the desired cooling or lubrication at the machining point there.

[0024] In this case, it is preferably provided that the exit openings 44, 45 are arranged as near as possible to the seat 13. It is furthermore preferably provided that the lateral chan-nels 42, 43 and/or the exit openings 44, 45 are configured and arranged such that, is to say for example, they have such a course through the holding region 11 and such a con-figuration of their opening that the exiting coolant impinges the cutting edge 20 and/or lateral flanks 26 adjoining the cutting edge 20 (or auxiliary cutting edges located there) and/or corners 27 of the cutting tool 2 which are located between the cutting edge 20 and the flanks 26. This ensures good cooling and lubrication of the flanks (auxiliary cutting edges) and cutting corners/radii of the cutting tool 2, even for long processing depths in bores.

[0025] It is furthermore preferably provided that the coolant channel 40 comprises a third lateral channel 46, which leads into a third exit opening 47. The third lateral channel 46 preferably likewise branches off from the main channel 41 and extends at an angle through the holding part 11, wherein it preferably leads into the third exit opening 47 on the upper side 162 of the support 16. In this case, the third lateral channel 46 and/or the third exit opening 47 is preferably configured and arranged such that exiting coolant pref-erably impinges the cutting edge 20 in order to bring about indirect cooling and lubrication at the machining point there.

[0026] In contrast to the embodiment shown in Figs. 4 to 6, the lateral channels 42, 43 in the embodiment of the coolant channel 40 shown in Fig. 7 do not branch off directly from the main channel 41; instead a transverse channel 48 is provided there, which extends transversely (preferably perpendicularly) to the main channel 41 (and transversely to the direction of the longitudinal extent of the holder 1) and branches off from the main channel 41 and from which at least the lateral channels 42, 43 in turn branch off.
This does not result in any substantial change in terms of the functionality, but it does enable alternative production of the coolant channel 40 in the holder 1 and possibly a better option for de-termining the direction of the lateral channels 43, 44 and therefore the exit direction of the coolant from the lateral channels 42, 43.

[0027] By means of the holder proposed according to the invention and the broaching tool with such a holder proposed according to the invention, an improved cooling and lubrica-tion of the cutting tool, in particular the cutting edge thereof and flanks (auxiliary cutting edges) adjoining the cutting edge and cutting corners or cutting radii is achieved.

[0028] Of course, the invention is not restricted to the exemplary embodiments shown.
Many different variations, for example with regard to the refinement of the cutting tool, for instance the arrangement, configuration and number of cutting edges and cutting corners, are directly conceivable. Accordingly, the number and arrangement of the coolant chan-nels or their exit openings can also be varied in order to achieve the desired purpose. The course of the entire coolant channel within the holder can also be configured differently, as illustrated in the figures.

Claims

1. A holder (1) for a broaching tool with a cutting tool (2) comprising a cutting edge (20) and with the holder (1) for holding the cutting tool (2), wherein the holder (1) comprises a clamping region (10) and a holding region (11), wherein the holding region (11) comprises, at its end facing away from the clamping re-gion (10), a seat (13) for the cutting tool (2), which is configured and arranged such that, when the cutting tool (2) is mounted into the seat (13), its cutting edge (20) projects be-yond the circumferential surface of the holding region (11), and wherein the holding region (11) comprises, on its circumferential surface (15), a support (16) for the cutting tool (2), characterized in that a coolant channel (40) extends inside the holder (1), wherein the coolant channel comprises two exit openings (44, 45) which, as seen in the circumfer-ential direction, are arranged laterally adjacent to the support (16) and/or in lateral surfac-es (161, 163) of the support (16).

2. The holder as claimed in claim 1, characterized in that the distance of the exit openings (44, 45) from the seat (13) is shorter than from the clamping region (10).

3. The holder as claimed in one of the preceding claims, characterized in that the coolant channel (40) and/or the exit openings (43, 44) are con-figured and arranged such that exiting coolant impinges the cutting edge (20) and/or lat-eral flanks (26) adjoining the cutting edge (20) and/or comers (27) of the cutting tool which are located between the cutting edge (20) and the flanks (26).

4. The holder as claimed in one of the preceding claims, characterized in that the coolant channel (40) comprises a third exit opening (47), which is arranged on the upper side (162) of the support (16).

5. The holder as claimed in claim 4, characterized in that the coolant channel (40) and/or the exit openings (44, 45, 47) are configured and arranged such that coolant exiting from the third exit opening (47) imping-es the cutting edge (20) and that coolant exiting from the two other exit openings (44, 45) impinges flanks (26) adjoining the cutting edge (20) and/or corners (27) of the cutting tool which are located between the cutting edge (20) and the flanks (26).

6. The holder as claimed in one of the preceding claims, characterized in that the coolant channel (40) comprises a main channel (41) extending through the clamping region (10) and two lateral channels (42, 43) branching off from the main channel (41) in the holding region (11), which two lateral channels lead into the lat-eral exit openings (44, 45).

7. The holder as claimed in claim 6, characterized in that the main channel (41) merges into a third lateral channel (46), which leads into a third exit opening (47) which is arranged on the upper side (162) of the sup-port (16).

8. The holder as claimed in claim 6 or 7, characterized in that the lateral channels (42, 43, 46) extend from the main channel (41) arranged centrally in the inside to the respective exit opening (44, 45, 47) at an angle through the holding region (11).

9. The holder as claimed in one of claims 6 to 8, characterized in that a transverse channel (48), which is arranged transversely to the lon-gitudinal axis of the holder and into which the main channel (41) leads and from which the lateral channels (42, 43) branch, is located between the main channel (41) and the lateral channels (42, 43, 46).

10. A broaching tool with a cutting tool (2) comprising a cutting edge (20) and with a holder (1) as claimed in one of claims 1 to 9 for holding the cutting tool (2).